Commits
Rafael J. Wysocki committed e5cc8ef3126
ACPI / PM: Provide ACPI PM callback routines for subsystems Some bus types don't support power management natively, but generally there may be device nodes in ACPI tables corresponding to the devices whose bus types they are (under ACPI 5 those bus types may be SPI, I2C and platform). If that is the case, standard ACPI power management may be applied to those devices, although currently the kernel has no means for that. For this reason, provide a set of routines that may be used as power management callbacks for such devices. This may be done in three different ways. (1) Device drivers handling the devices in question may run acpi_dev_pm_attach() in their .probe() routines, which (on success) will cause the devices to be added to the general ACPI PM domain and ACPI power management will be used for them going forward. Then, acpi_dev_pm_detach() may be used to remove the devices from the general ACPI PM domain if ACPI power management is not necessary for them any more. (2) The devices' subsystems may use acpi_subsys_runtime_suspend(), acpi_subsys_runtime_resume(), acpi_subsys_prepare(), acpi_subsys_suspend_late(), acpi_subsys_resume_early() as their power management callbacks in the same way as the general ACPI PM domain does that. (3) The devices' drivers may execute acpi_dev_suspend_late(), acpi_dev_resume_early(), acpi_dev_runtime_suspend(), acpi_dev_runtime_resume() from their power management callbacks as appropriate, if that's absolutely necessary, but it is not recommended to do that, because such drivers may not work without ACPI support as a result. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>